Vibration attenuation performance of wind turbine tower using a prestressed tuned mass damper under seismic excitation

With the rapid development of large megawatt wind turbines,the operation environment of wind turbine towers(WTTs)has become increasingly complex.In particular,seismic excitation can create a resonance response and cause excessive vibration of the WTT.To investigate the vibration attenuation performance of the WTT under seismic excitations,a novel passive vibration control device,called a prestressed tuned mass damper(PS-TMD),is presented in this study.First,a mathematical model is established based on structural dynamics under seismic excitation.Then,the mathematical analytical expression of the dynamic coefficient is deduced,and the parameter design method is obtained by system tuning optimization.Next,based on a theoretical analysis and parameter design,the numerical results showed that the PS-TMD was able to effectively mitigate the resonance under the harmonic basal acceleration.Finally,the time-history analysis method is used to verify the effectiveness of the traditional pendulum tuned mass damper(PTMD)and the novel PS-TMD device,and the results indicate that the vibration attenuation performance of the PS-TMD is better than the PTMD.In addition,the PS-TMD avoids the nonlinear effect due to the large oscillation angle,and has the potential to dissipate hysteretic energy under seismic excitation.

Tower crane path planning based on improved ant colony algorithm

In order to solve the problem of path planning of tower cranes,an improved ant colony algorithm was proposed.Firstly,the tower crane was simplified into a three-degree-of-freedom mechanical arm,and the D-H motion model was established to solve the forward and inverse kinematic equations.Secondly,the traditional ant colony algorithm was improved.The heuristic function was improved by introducing the distance between the optional nodes and the target point into the function.Then the transition probability was improved by introducing the security factor of surrounding points into the transition probability.In addition,the local path chunking strategy was used to optimize the local multi-inflection path and reduce the local redundant inflection points.Finally,according to the position of the hook,the kinematic inversion of the tower crane was carried out,and the variables of each joint were obtained.More specifically,compared with the traditional ant colony algorithm,the simulation results showed that improved ant colony algorithm converged faster,shortened the optimal path length,and optimized the path quality in the simple and complex environment.

Comparison between seismic analysis of twisting and regular 52-story towers considering soil-structure interaction

A dynamic analysis of both twisting and regular towers is carried out to determine the results of considering soil-structure interaction(SSI)on high-rise buildings.In addition,the difference between the seismic performance of using twisting towers over regular ones is investigated.The twisting tower is a simulation of the Evolution Tower(Moscow).The towers’skeletons consist of RC elements and rest on a reinforced concrete piled-raft foundation.The soil model is considered as multi-layered with the same soil properties as the zone chosen for the analysis(New Mansoura City,Egypt).The only difference between both towers is their shape in elevation.The whole system is modelled and analyzed in a single step as one full 3D model,which is known as the direct approach in SSI.All analyses are carried out using finite-element software(Midas GTS NX).Dynamic output responses due to three records of seismic loads are proposed and presented in some graphs.Based on the results,it is concluded that SSI has a considerable effect on the dynamic response of tall buildings mainly because of the foundation flexibility,as it leads to lengthening the vibration period,increasing the story drift and the base shear for both cases.

Research on Transmission Line Tower Tilting and Foundation State Monitoring Technology Based onMulti-Sensor Cooperative Detection and Correction

The transmission line tower will be affected by bad weather and artificial subsidence caused by the foundation and other factors in the power transmission.The tower’s tilt and severe deformation will cause the building to collapse.Many small changes caused the tower’s collapse,but the early staff often could not intuitively notice the changes in the tower’s state.In the current tower online monitoring system,terminal equipment often needs to replace batteries frequently due to premature exhaustion of power.According to the need for real-time measurement of power line tower,this research designed a real-time monitoring device monitoring the transmission tower attitude tilting and foundation state based on the inertial sensor,the acceleration of 3 axis inertial sensor and angular velocity raw data to pole average filtering pre-processing,and then through the complementary filtering algorithm for comprehensive calculation of tilt angle,the system meets the demand for inclined online monitoring of power line poles and towers regarding measurement accuracy,with low cost and power consumption.The optimization multi-sensor cooperative detection and correction measured tilt angle result relative accuracy can reach 1.03%,which has specific promotion and application value since the system has the advantages of unattended and efficient calculation.

Impact of Crosswind on Steady-State and Dynamic Performance of Natural Draft Dry Cooling Tower Group:A Numerical Analysis

This study investigates the performance of a natural draft dry cooling tower group in crosswind conditions through numerical analysis.A comprehensive three-dimensional model is developed to analyze the steady-state and dynamic behavior of the towers.The impact of wind speed and direction on heat rejection capacity and flow patterns is examined.Results indicate that crosswinds negatively affect the overall heat transfer capacity,with higher crosswind speeds leading to decreased heat transfer.Notably,wind direction plays a significant role,particularly at 0°.Moreover,tower response time increases with higher crosswind speeds due to increased turbulence and the formation of vortices.The response times are generally similar for wind directions of 45°and 90°,but differ when facing 0,where the leeward tower exhibits a shorter response time compared to the windward tower.These findings provide valuable insights into the performance of natural draft dry cooling tower groups under crosswind conditions,which can inform the design and operation of similar systems in practical applications.

Design Optimization of a Lattice Tower: Structure and Foundations

Produced in power plants, electrical energy is transported to places of consumption via the electricity network. At the heart of this network are the supports that allow electricity to be efficiently transported over long distances, guaranteeing the security and supply of energy to the various centers of use. In the construction of a line, supports occupy an important part in terms of safety and construction cost. It is therefore essential to optimize their use to reduce the cost of transmission lines. This work addresses this problem, which focuses on the optimal utilization of X-lattice towers in the construction of overhead power lines. The challenge is to reconcile the search for optimal cost and respect for the design, resistance and service constraints of the structure. To do this, a parameter having a strong correlation with the weight, foundation and construction cost of the X-lattice tower for 161 kV lines is determined as an important cost variable. This parameter is the wheelbase of the towers. The junction point between the structure and the foundations is obtained by measuring the forces at the base of the tower following the lowering of the loads. These efforts make it possible to size foundations which are of the inverted or isolated sole type. The results obtained reveal that from 8 meters in width, the wheelbase gradually changes until the optimum is obtained at 6.29 meters. With this wheelbase, the production cost is optimal. It clearly emerges from this study that the construction of lattice pylons with a wheelbase of approximately 6.29 meters makes it possible to optimize the cost of construction of 161 kV lines in the Republic of Benin.

Tower Semiconductor Acquisition: Advancing Intel’s Presence in the Global Market

This paper delves into the economic event surrounding Intel Corporation’s high-profile acquisition of Tower Corporation.It aims to investigate the reasons behind Intel’s decision to acquire Tower,employ the SWOT analysis method to evaluate the event,and examine its impact on relevant stakeholders.The findings indicate that Intel’s acquisition of Tower was driven by objectives such as strengthening business areas,expanding market share,technological innovation and development,and future development strategy.Through the application of SWOT analysis,it becomes evident that the advantages of the acquisition lie in strengthening technical capabilities and expanding business segments,while simultaneously facing challenges such as integration complexities and pressure.The significance of this paper lies in gaining a comprehensive understanding of the strategic motivations and potential impacts associated with corporate acquisitions,thereby providing valuable insights for decision-making processes.The innovation lies in the comprehensive utilization of SWOT analysis to holistically evaluate the acquisition event,enabling a thorough assessment of its various aspects.For government and policymakers,they should strength regulation of corporate takeovers to ensure fair and transparent market competition,provide support and incentives,and strength cooperation to develop common policies and norms.As for enterprises,it is advised that strategic planning and comprehensive consideration should be formulated and carried out when making acquisitions.Also,stakeholders should actively participate in and monitor the process of corporate acquisition discussion and decision-making,and strengthen cooperation to ensure fair competition,maximizing the interests of all parties.

Evaluation of Driver-Induced Human Errors in Smart Construction Tower Crane Operations Based on DEMATEL-ISM-MICMAC

With the advent of Industry 4.0, smart construction sites have seen significant development in China. However, accidents involving digitized tower cranes continue to be a persistent issue. Among the contributing factors, human unsafe behavior stands out as a primary cause for these incidents. This study aims to assess the human reliability of tower crane operations on smart construction sites. To proactively enhance safety measures, the research employs text mining techniques (TF-IDF-Truncated SVD-Complement NB) to identify patterns of human errors among tower crane operators. Building upon the SHEL model, the study categorizes behavioral factors affecting human reliability in the man-machine interface, leading to the establishment of the Performance Shaping Factors (PSFs) system. Furthermore, the research constructs an error impact indicator system for the intelligent construction site tower crane operator interface. Using the DEMATEL method, it analyzes the significance of various factors influencing human errors in tower crane operations. Additionally, the ISM-MICMAC method is applied to unveil the hierarchical relationships and driving-dependent connections among these influencing factors. The findings indicate that personal state, operating procedures, and physical environment directly impact human errors, while personal capability, technological environment, and one fundamental organizational management factor contribute indirectly. .

A robust protocol to compute wind load coefficients of telecommunication towers and antennas using numerical simulation for risk and resilience assessment

An accurate estimation of wind loads on telecommunication towers is crucial for design,as well as for perform-ing reliability,resilience,and risk assessments.In particular,drag coefficient and interference factor are the most significant factors for wind load computations.Wind tunnel tests and computational fluid dynamics(CFD)are the most appropriate methods to estimate these parameters.While wind tunnel tests are generally preferred in practice,they require dedicated facilities and personnel,and can be expensive if multiple configurations of tower panels and antennas need to be tested under various wind directions(e.g.,fragility curve development for system resilience analysis).This paper provides a simple,robust,and easily accessible CFD protocol with widespread applicability,offering a practical solution in situations where wind tunnel testing is not feasible,such as complex tower configurations or cases where the cost of running experiments for all the tower-antennas configurations is prohibitively high.Different turbulence models,structural and fluid boundary conditions and mesh types are tested to provide a streamlined CFD modeling strategy that shows good convergence and balances accuracy,computational time,and robustness.The protocol is calibrated and validated with experimental studies available in the literature.To demonstrate the capabilities of the protocol,three lattice tower panels and antennas with different configurations are analyzed as examples.The protocol successfully estimates the drag and lateral wind loads and their coefficients under different wind directions.Noticeable differences are observed between the esti-mated wind loads with this protocol and those computed by a simple linear superposition used in most practical applications,indicating the importance of tower-antenna interaction.Also,as expected,the wind loads recom-mended by design codes overestimate the simulated results.More importantly,the telecommunication design codes inadequately identify the most favorable wind directions that are associated with the lowest wind loads,while the results of the proposed protocol align with observations from experimental studies.This information may be used to select the tower orientation before construction.The findings of this study are of importance for the telecommunication industry,which seeks reliable results with minimal computational efforts.In addition,it enhances the fragility analysis of telecommunication towers under strong winds,and the portfolio risk and resilience assessment of telecommunication systems.

Tower节点集上的极小次数牛顿基

将关于张量积格点的lower子集上Lagrange插值问题的极小次数牛顿基推广到tower节点子集上.解决了二元Lagrange插值牛顿基问题,把tower节点集的概念推广到任意多维情形,以三维为例给出了相应的Lagrange插值极小次数牛顿基,并给出了计算三维tower节点集合消逝理想的约化Grbner基的快速算法.

Adsorption Properties of Adsorption Tower Filled with Calcium Superphosphate on NH_3 Emitted from Composting System of Animal Wastes

[Objective] This study aimed to investigate the adsorption properties of the adsorption tower filled with calcium superphosphate on ammonia volatilized with aer- ation. [Method] Adsorption tower filled with calcium superphosphate was adopted as experimental apparatus, which was constructed by poly vinyl chloride （PVC） circular tubes. With hartshorn as the source of ammonia volatilization, the effect of different ratios of height to diameter of the tower filled with equal amount of calcium super-phosphate on ammonia adsorption was investigated. In addition, adsorption tower with height-diameter ratio of 9.9 was selected to adsorb the ammonia emitted from the composting systems of pig manure and chicken manure with optimized and reg- ulated carbon-nitrogen ratio. [Result] Under certain volatilization rate, calcium super- phosphate particles in the adsorption tower could effectively adsorb the ammonia, and the adsorption efficiency was enhanced with the increase of height-diameter ra-tio, which could reach above 90% with height-diameter ratio of more than 1.1; the ammonia emitted from composting systems of pig manure and chicken manure with optimized and regulated carbon-nitrogen ratio could be completely absorbed using adsorption tower with height-diameter ratio of 9.9 filled with calcium superphosphate accounting for about 8% of the weight of composting materials. [Conclusion] Experi- mental results of this study provided reference for the application of adsorption tower filled with calcium superphosphate in the treatment of waste gas emitted from com- posting materials.

运用Sawyer Tower电路测试薄膜铁电性能

声表面波煤矿瓦斯传感器是一种新型瓦斯传感器,PZT基高压电铁电薄膜是该类传感器制备的理想功能材料,铁电性作为PZT基铁电薄膜的另一个重要性能对传感器的工作特点和稳定性具有重要影响。因而,测试并掌握具有高压电性铁电薄膜的铁电性也是器件材料表征的一项重要工作。采用Sawyer Tower电路原理,自主设计铁电测试电路,制备PZT基铁电薄膜,并利用该电路测试薄膜的铁电性。由实验结果可知,自主设计的Sawyer Tower电路能简便、有效、准确和直观的测试薄膜的铁电性能,有望广泛应用于薄膜铁电性能测试及研究。

Tower支持下的App混合式学习研究——以“学习科学与技术”课程为例

文章从Tower支持创建团队、发布任务、协作讨论等功能出发,以"学习科学与技术"课程为例,构建了Tower支持下的App混合式学习模式,设计了基于该模式的教学实施流程,验证了Tower支持下的App混合式学习能有效地促进教学和学习,为相关领域的理论和实践研究提供了借鉴。

“Problem of Towers of Hanoi”仿真软件的设计

"Problem of Towers of Hanoi",用递归的方法能很容易地解决问题,不用递归的方法将会是比较困难,因为随着参与盘子数的不断增多,计算时间和复杂度将会不断增多。运用仿真软件能清晰地勾勒出每个盘子的移动轨迹并给出详细的移动步骤,这将会使此问题能更形象、更直观的解决。

基于Hanoi Tower算法的对等组认证模型研究

运用对称密码体制、公钥体制和数字签名技术,针对基于中间服务器架构的P2P网络,提出了一个公平且不可抵赖的HanoiTower安全认证协议算法,给出了协议模型实现的算法描述,然后对协议算法的性能和安全性进行了分析,并以某大型企业设计所“基于P2P网络构建的产品开发协同工作系统”为背景,分析了模型实现的若干关键技术问题。

基于Tower的翻转课堂教学模式及其应用研究——以“网络学习共同体”为视角

随着互联网与教育不断融合,翻转课堂为提高学习者的学习动机和学习效果创造了新的契机。文章在分析翻转课堂与网络学习共同体关系及Tower的功能特点的基础上,提出了基于Tower的翻转课堂教学模式,并将此模式应用到教学过程中。研究表明,在基于Tower的翻转课堂中,师生角色有所转变,交互程度有所提升,并且高效完成了知识共享和转移;但同时也发现,学习者参与度较低、自主思考能力较薄弱、教师角色定位不明确等因素会对共同体的学习效果产生负面影响。为此,文中有针对性地提出了改进建议。

考虑基础-土相互作用的采空区输电铁塔承载特性研究

采空区地表沉降后,输电铁塔基础可能发生沉降、倾斜,影响杆件变形及轴力分布,导致杆件失效。以某采空区750 kV输电铁塔为研究对象,建立了输电铁塔、基础与土相互作用的有限元模型,对不同基础型式、不同沉降位置的塔腿杆件轴力分布及变形影响规律进行了分析,同时分析了铁塔基础的受力特性。结果表明,当考虑相互作用影响时,杆件轴力和节点位移随沉降值呈非线性变化;相较于独立基础,不同沉降位置对大板基础的塔腿主材、斜材轴力的影响更大;当基础处于沉降位置时,防护大板能有效减小基础所受应力。

缘于巴别塔(the Tower of Babel)的故事——访江苏绿源新材料有限公司董事长林永飞

林永飞，江苏绿源新材料有限公司董事长，中国塑料加工工业协会聚氨酯制品专业委员会会长，中国塑料加工工业协会副理事长。

Hanoi Tower问题动态演示——C图形设计

通过对HanoiTower移动递归特性的分析 ,利用TurboC 2 .0系统中相关图形处理函数 。

Rapid seismic analysis methodology for in-service wind turbine towers

The wind energy industry has been growing rapidly during the past decades.Along with this growth,engineering problems have gradually emerged in the wind power industry,including those related to the structural reliability of turbine towers.This study proposes a rapid seismic analysis methodology for existing wind turbine tower structures.The method is demonstrated and validated using a case study on a 1.5 MW tubular steel wind turbine tower.Three finite element(FE)models are developed first.Field tests are conducted to obtain the turbine tower’s vibrational characteristics.The tests include(1) remotely measuring the tower vibration frequencies using a long range laser Doppler Vibrometer and(2) monitoring the tower structural vibration by mounting accelerometers along the height of the tubular structure.In-situ measurements are used to validate and update the FE models of the wind turbine tower.With the updated FE model that represents the practical structural conditions,seismic analyses are performed to study the structural failure,which is defined by the steel yielding of the tubular tower.This research is anticipated to benefit the management of the increasing number of wind energy converters by providing an understanding of the seismic assessment of existing tubular steel wind turbine towers.